1. Field of the Invention
The present invention generally relates to electronic devices. More particularly, the invention relates to interfaces between electronic devices, for example for a memory controller and a memory circuit.
2. Description of the Related Art
Integrated circuits typically have dedicated interface circuits to communicate with other integrated circuits and other systems. These dedicated interface circuits are typically interconnected with conductors that carry signals from one integrated circuit to another. Some signal lines are terminated with a termination impedance that approximates the characteristic impedance of the signal line. These terminations can increase communication reliability by reducing unwanted signal reflections on the signal line. When the characteristic impedance of a signal line is uniform across its length, and the termination impedance matches the characteristic impedance of the signal line, signal reflections may be substantially reduced.
Signals that travel from one integrated circuit to another are becoming faster and faster. As signal speeds increase, the effects of poorly terminated signal lines become more pronounced, and proper terminations become more important.
For high speed interfaces, it is necessary to reload in short times, which means low impedance on the signal line and a high current.